Loss calculation method and loss calculating device

ABSTRACT

A first calculating unit calculates a load current of each distribution facility based on a sending voltage in a power source facility and load information on power consumption facilities in an electrical circuit including the power source facility, the distribution facilities, and the power consumption facilities connected to one another to form the electrical circuit. A second calculating unit calculates the amount of power loss in each distribution facility based on the calculated load current of each distribution facility.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 14/331,663,filed Jul. 15, 2014, which is based upon and claims the benefit ofpriority of the prior Japanese Patent Application No 2013-178653, filedon Aug. 29, 2013, the entire contents of which are incorporated hereinby reference.

FIELD

The embodiments discussed herein are related to a loss calculationmethod and a loss calculating device.

BACKGROUND

In power distribution systems, widely used are distribution facilitieswhose facility capacity can withstand a peak load. The facility capacityof such a distribution facility is determined based on a peak loadcurrent derived in installation of the distribution facility. Every timethe load state is changed after the installation or the distributionfacility is replaced because of aging, the facility capacity of thedistribution facility is determined based on the latest load state.Conventional technologies are described in Japanese Laid-open PatentPublication No. 2007-080260, for example.

Distribution facilities, such as transformers, consume electric powerthemselves. The electric power consumed by the distribution facilitiesis generated and then consumed while being transmitted to a consumer.Because the electric power is not used by the consumer, it is consideredas a loss. Such power loss in a distribution system is referred to as adistribution loss. The distribution loss increases as the distributioncapacity of a distribution system decreases. When the distributioncapacity of the distribution facility decreases depending on the load,the distribution loss increases.

It has been difficult to grasp the electric current value in eachdistribution facility of the distribution system, and thus thedistribution loss of each distribution facility has not been graspedwith high accuracy.

SUMMARY

According to an aspect of an embodiment, a computer-readable recordingmedium stores therein a program. The program causes a computer toexecute a process that includes calculating a load current of eachdistribution facility based on a sending voltage in a power sourcefacility and load information on power consumption facilities in anelectrical circuit including the power source facility, the distributionfacilities, and the power consumption facilities connected to oneanother to form the electrical circuit; and calculating an amount ofpower loss in each distribution facility based on the calculated loadcurrent of each distribution facility.

The object and advantages of the invention will be realized and attainedby means of the elements and combinations particularly pointed out inthe claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and arenot restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of a functional configuration of a losscalculating device according to a first embodiment of the presentinvention;

FIG. 2 is a schematic of an aspect of entities;

FIG. 3 is an example diagram of the interrelation of the entities;

FIG. 4 is an example diagram of a location table;

FIG. 5 is an example diagram of a unit table;

FIG. 6 is an example diagram of a span table;

FIG. 7 is an example diagram of a node table;

FIG. 8 is an example diagram of a branch table

FIG. 9 is an example diagram of a current node table;

FIG. 10 is an example diagram of a current branch table;

FIG. 11 is a first example diagram of a graph structure of adistribution system;

FIG. 12 is a second example diagram of the graph structure of thedistribution system;

FIG. 13 is an example diagram of a load table;

FIG. 14 is an example diagram of the amount of power loss in a currentsystem;

FIG. 15 is an example diagram of the amount of power loss in the currentsystem;

FIG. 16 is an example graph of the amount of power loss in eachpredetermined period in specified facilities;

FIG. 17 is an example graph of the amount of power loss in eachpredetermined period in units of the types of distribution facilities;

FIG. 18 is an example pie chart of the amount of power loss per day inunits of the types of the distribution facilities;

FIG. 19 is a flowchart of distribution management processing accordingto the first embodiment;

FIG. 20 is a flowchart Of the distribution management processingaccording to the first embodiment;

FIG. 21 is a flowchart of loss calculation processing according to thefirst embodiment;

FIG. 22 is a block diagram of a functional configuration of a losscalculating device according to a second embodiment of the presentinvention;

FIG. 23 is an example diagram of unit price information;

FIG. 24 is an example diagram of facility performance information;

FIG. 25 is an example graph of a loss price in each predetermined periodin units of the types of the distribution facilities;

FIG. 26 is a diagram for explaining a change in the loss price caused byreplacement of a distribution facility;

FIG. 27 is a diagram for explaining a change in the unit price caused byreplacement of the distribution facility;

FIG. 28 is an example diagram of comparison of the accumulated value ofthe loss price per year with the difference in the unit price;

FIG. 29 illustrates an example of display of a result of simulation; and

FIG. 30 is an example block diagram for explaining a computer thatexecutes a loss calculation program according to the first embodiment toa third embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present invention will be explained withreference to the accompanying drawings. The embodiments are not intendedto limit the disclosed technology. The embodiments may be appropriatelycombined without contradicting the processing contents.

[a] First Embodiment

Configuration of a Loss Calculating Device

FIG. 1 is a block diagram of a functional configuration of a losscalculating device according to a first embodiment of the presentinvention. A loss calculating device 10 illustrated in FIG. 1 isprovided to a distribution system between a substation of an electricpower supplier and a load facilities of a consumer to perform losscalculation processing for calculating a distribution loss in eachdistribution facility.

An aspect on the loss calculating device 10 may be provided as a Webserver that performs the loss calculation processing or a cloud thatsupplies services relating to the loss calculation processing byoutsourcing. Another aspect of the loss calculating device 10 may beprovided by preinstalling or installing a loss calculation programsupplied as package software or online software on a desired computer.

As illustrated in FIG. 1, the loss calculating device 10 is communicablyconnected to other devices including a client terminal 30 and a smartmeter 50 via a predetermined network. Examples of the network includedesired types of wired or wireless communication networks, such as theInternet, a local area network (LAN), and a virtual private network(VPN). A desired number of client terminals 30 and smart meters 50 maybe connected.

The client terminal 30 is a terminal device on a recipient side thatreceives the loss calculation service. Examples of the client terminal30 include a fixed terminal, such as a personal computer (PC), and amobile terminal, such as a mobile phone, a personal handy-phone system(PHS), and a personal digital assistant (PDA). The client terminal 30 isused by a member of the electric power supplier, such as a person incharge and an administrator in a distribution department.

The smart meter 50 is an electric power meter with a communicationfunction. The smart meter 50 is connected to a distribution board of theconsumer, for example. An aspect of the smart meter 50 measures electricpower used by the load facilities of the consumer every predeterminedperiod (e.g., every 30 minutes). The smart meter 50 accumulates andmeasures the electric power used by the load facilities. In thedescription below, the value of the accumulated and measured electricpower used by the load facilities may be referred to as “the amount ofpower consumption”. The smart meter 50 transmits the amount of powerconsumption to the loss calculating device 10. While the smart meteruploads the amount of power consumption every predetermined period inthis example, the smart meter may upload the amount of power consumptionintermittently. The smart meter 50 may upload the amount of powerconsumption not actively but in response to a request from the losscalculating device 10.

As illustrated in FIG. 1, the loss calculating device 10 includes acommunication interface (I/F) 11, a storage unit 13, and a control unit19. The loss calculating device 10 may include various types offunctional units included in a known computer, such as various types ofinput-output devices and image-capturing devices, besides the functionalunits illustrated in FIG. 1.

The communication I/F 11 controls communications with other devicesincluding the client terminal 30 and the smart meter 50, for example.Examples of an aspect of the communication I/F 11 include a networkinterface card, such as a LAN card. The communication I/F 11, forexample, receives various types of information, such as various types ofinstruction information, from the client terminal 30, and transmitsimage data of various types of screens from the loss calculating device10 to the client terminal 30.

The storage unit 13 is a storage device that stores therein varioustypes of computer programs, such as an operating system (OS), adistribution management program, and a loss calculation program executedby the control unit 19. Examples of an aspect of the storage unit 13include a semiconductor memory device such as a flash memory, and astorage device such as a hard disk and an optical disc. The storage unit13 is not limited to the types of storage devices described above andmay be a random access memory (RAM) or a read only memory (ROM).

The storage unit 13 scores therein positional information 14, facilityinformation 15, electrical connection information 16, distributionsystem information 17, load information 18, and power loss amountinformation 20 as an example of data used by a computer program executedby the control unit 19. The storage unit 13 may also store therein otherelectronic data, such as map information containing the distributionsystem controlled by the electric power supplier, besides theinformation described above.

The loss calculating device 10 according to the present embodimentmanages the distribution system in three ways: position management tomanage a position at which a facility is located; facility management tomanage each facility; and electrical connection management to managefacilities electrically connected to each other.

In the position management the loss calculating device 10 uses aposition “location” at which a predetermined facility, such as asubstation, a utility pole, and a transformer, out of the facilitiesconstituting the distribution system as an entity. In the facilitymanagement, the loss calculating device 10 uses a facility “unit”relating to one position out of the facilities constituting thedistribution system and a facility “span” relating to two positions asentities. In the electrical connection management, the loss calculatingdevice 10 uses a connection “node” at which facilities are electricallyconnected to each other and a facility “branch” determined by aplurality of connections as entities.

FIG. 2 is a schematic of an aspect of the entities. As illustrated inFIG. 2, examples of the location include a position at which a facilityprovided in a non-bridging manner, such as a utility pole P and a poletransformer TR, is located. In addition to this, the concept of thelocation also includes a position at which a substation (SS), which isnot illustrated, is located and a position at which a transformer islocated. While the facilities provided on the ground are exemplifiedabove, the concept of the location also includes a position at which afacility provided under the ground, such as a manhole and a hand hole,is located.

Examples or the unit include the utility pole P, a switch SW, and thepole transformer TR. In addition to this, the concept of the unit alsoincludes the SS, a step voltage regulator (SVR), various types ofmeters, such as the smart meter 50, and a manhole and a hand holeprovided under the ground, none of which is illustrated.

Examples of the span include an electric wire WH provided to ahigh-voltage system that transmits high-voltage power between the SS andthe pole transformer TR, that is, what is called a “high-voltage wire”.Examples of the span also include an electric wire WL provided to asection between the pole transformer TR and a lead-in wire in alow-voltage system that transmits low-voltage power between the poletransformer TR and the load facilities of the consumer, that is, what iscalled a “low-voltage wire”. Examples of the span also include anelectric wire provided to a section between the lead-in wire and theload facilities, that is, what is called a “lead-in wire”. Examples ofthe span also include a cable buried in the ground. A plurality of(e.g., three or two) electric wires W, such as the high-voltage wires WHand the low-voltage wires WL, provided between the utility poles P maybe collectively considered as a span.

Examples of the node include a connection of the high-voltage wire WHand the switch SW illustrated in the enlarged view 21 in FIG. 2, aconnection of the high-voltage wire WH and the pole transformer TR, anda connection of the pole transformer TR and the low-voltage wire WL. Inaddition to this, the concept of the node also includes a point at whicha high-voltage wire WH21 a and a high-voltage wire WH21 b are connectedas illustrated in the enlarged view 22 in FIG. 2. Specifically, evenwhen the high-voltage wire WH21 a and the high-voltage wire WH21 b arehung by a utility pole P serving as a through pole, the high-voltagewire WH21 a and the high-voltage wire WH21 b are considered to beelectrically connected. A point at which the high-voltage wires WHs areconnected is considered to be a virtual node.

Examples of the branch include various types of facilities including theutility pole P, the high-voltage wire WH, the switch SW, the poletransformer TR, and the low-voltage wire WL illustrated in FIG. 2. Inaddition to this, the concept of the branch also includes the SS, thelead-in wire, the smart meter 50, and the load facilities, none of whichis illustrated. Facilities positioned at an end, such as the SS and theload facilities, may have one node alone.

The entities including the location, the unit, the span, the node, andthe branch have the relation illustrated in FIG. 3. FIG. 3 is an examplediagram of the interrelation of the entitles. As illustrated in FIG. 3,the unit and the span are interrelated with each other in that thepositions thereof are collectively managed with respect to the location.Furthermore, the unit and the span are interrelated with each other inthat the facilities thereof are collectively managed with respect to thebranch. The node is interrelated in that the connection thereof iscollectively managed with respect to the location and the branch.

Referring back to FIG. 1, the positional information 14 includes alocation table 14 a that manages the location. The facility information15 includes a unit table 15 a that manages the unit and a span table 15b that manages the span. The electrical connection information 16includes a node table 16 a that manages the node and a branch table 16 bthat manage the branch. The distribution system information 17 includesa current node table 17 a and a current branch table 17 b, which will bedescribed later.

In an aspect of the location table 14 a, items including a positionidentifier (ID), position identification, a longitude, and a latitudeare associated with one another. The “position ID” is identificationinformation for identifying a position at which a facility is located.The “position identification” indicates identification of the type ofthe position, including a substation (SS), a utility pole (POLE), and aload facility (LOADL), for example. The information stored in thelocation table 14 a is acquired from other existing systems, such as adistribution facility management system that manages the facilities ofthe distribution system. The location table 14 a acquires positionalinformation on a specific facility, such as a substation, a utilitypole, and a transformer.

FIG. 4 is an example diagram of the location table 14 a. It is indicatedthat the location of a position ID “SS0001” illustrated in FIG. 4 ispositioned at 128 degrees 08 minutes 48 seconds 66 east longitude and 50degrees 27 minutes 23 seconds 016 north latitude and has an SS, forexample. The various types of IDs illustrated in the figures followingFIG. 4 each have a character string with which the type of the facilitycan be identified, such as “SS” representing a substation, “PO”representing a utility pole, and “LL” representing a load facility, atthe head of the character string constituting the ID. The various typesof IDs do not necessarily each have a character string with which thetype of the facility can be identified at the head of the characterstring constituting the ID. The various types of IDs may each have avalue with which the facility can be uniquely identified. In thisexample, the longitude and the latitude are used as the items thatidentify the position of the facility. Alternatively, other items, suchas a local coordinate value and an address, may be used.

In an aspect of the unit table 15 a, items including a facility ID, aposition ID, a type, and attribute information are associated with oneanother. The “facility ID” is identification information for identifyinga facility, and the unit table 15 a stores therein the facility ID of aunit alone. The “type” indicates the type of the unit, including autility pole (POLE), a switch (SW), a pole transformer (BANK), and aload facility (LOADL), for example. The “attribute information” isinformation on an attribute of the unit, such as a model number andperformance of the unit. If the unit is a transformer, for example,capacity and a voltage ratio of the transformer are registered. Thecapacity of the transformer may be used to calculate a voltage drop whenelectrical connection information on the facilities of the currentsystem is extracted. If the unit is a transformer, for example, aresistance, a reactance, and a voltage ratio of the transformer areregistered. The information stored in the unit table 15 a is acquiredfrom other existing systems, such as a distribution facility managementsystem. The unit table 15 a registers therein attribute information on afacility classified as a unit out of the acquired attribute informationon the facilities.

FIG. 5 is an example diagram of the unit table 15 a. It is indicatedthat the unit of a facility ID “PO0001P1” illustrated in FIG. 5 is autility pole located at the position corresponding to a position ID“PO0001”, that is, at 128 degrees 08 minutes 41 seconds 76 eastlongitude and 50 degrees 27 minutes 23 seconds 021 north latitude asillustrated in FIG. 4, for example. It is also indicated that the unitof a facility ID “PO000101” illustrated in FIG. 5 is a switch located atthe position corresponding to the position ID “PO0001”, that is, at 128degrees 08 minutes 41 seconds 76 east longitude and 50 degrees 27minutes 23 seconds 021 north latitude as illustrated in FIG. 4. It isalso indicated that the unit of a facility ID “PO000701” illustrated inFIG. 5 is a pole transformer having a voltage ratio of 1 and located atthe position corresponding to a position ID “PO0007”, that is, at 128degrees 08 minutes 34 seconds 30 east longitude and 50 degrees 27minutes 27 seconds 844 north latitude as illustrated in FIG. 4.

In an aspect of the span table 15 b, items including a facility ID, aposition ID₁, a position ID₂, a type, and attribute information areassociated with one another. The “facility ID” is identification,information, for identifying a facility, and the span table 15 b storestherein the facility ID of a span alone. The “position ID₁” is aposition ID of one of two position IDs relating to the span, whereas the“position ID₂” is a position ID of the other of the two position IDsrelating to the span. The “type” indicates the type of the span,including a high-voltage wire, a low-voltage wire, and a lead-in wire,for example. The “attribute information” is information on an attributeof the span, such as a model number, the thickness, a material, the spanlength, a resistance per unit (m), and a reactance per unit (m) of thespan. The span length, the resistance per unit, and the reactance perunit may be used to calculate a voltage drop when the electricalconnection information on the facilities of the current system isextracted. The information stored in the span table 15 b is acquiredfrom other existing systems, such as a distribution facility managementsystem. The span table 15 b registers therein attribute information on afacility classified as a span out of the acquired attribute informationon the facilities.

FIG. 6 is an example diagram of the span table 15 b. It is indicatedthat the span of a facility ID “SP0001” illustrated in FIG. 6 is athree-phase high-voltage wire provided to a section between the positioncorresponding to a position ID₁ “SS0001” and the position correspondingto a position ID₂ “PO0001”, for example. As explained with reference toFIG. 4, the section corresponds to a section from 128 degrees 08 minutes48 seconds 66 east longitude and 50 degrees 27 minutes 23 seconds 016north latitude to 128 degrees 08 minutes 41 seconds 76 east longitudeand 50 degrees 27 minutes 23 seconds 021 north latitude. It is alsoindicated that the span, length of the span of the facility ID “SP0001”is “21 m”, that the resistance is “220 Ω/m”, and that the reactance is“150 Ω/m”. In the type illustrated in FIG. 6, 3H indicates that the spanis a single-phase three-wire high-voltage wire, 3L indicates that thespan is a single-phase three-wire low-voltage wire, and a blankindicates that the span is a lead-in wire.

In an aspect of the node table 16 a, items including a node ID and aposition ID are associated with each other. The “node ID” isidentification information for identifying a node. The informationstored in the node table 16 a is acquired from other existing systems,such as a distribution facility management system and a distributionautomation system that monitors a distribution system and remotelyoperates a switch. A node is, for example, extracted from information onfacilities of a low-voltage system acquired from the distributionfacility management system or information on facilities of ahigh-voltage system acquired from the distribution automation system.Subsequently, the node is registered in the node table 16 a in a mannerassociated with the position thereof.

FIG. 7 is an example diagram of the node table 16 a. It is indicatedthat the connection of a node ID “SS0001N01” illustrated in FIG. 7 islocated at the position corresponding to the position ID “SS0001”, thatis, at 128 degrees 08 minutes 48 seconds 66 east longitude and 50degrees 27 minutes 23 seconds 016 north latitude as illustrated in FIG.4, for example. It is also indicated that the connections of node IDs“PO0001N01” and “PO0001N02” illustrated in FIG. 7 are located at thesame position corresponding to the position ID “PO0001”, that is, at 128degrees 08 minutes 41 seconds 76 east longitude and 50 degrees 27minutes 23 seconds 021 north latitude as illustrated in FIG. 4.

In an aspect of the branch table 16 b, items including a branch ID, anode ID₁, a node ID₂, a facility ID, and an open-close section areassociated with one another. The “branch ID” is identificationinformation for identifying a branch. The “node ID₁” is a node ID of oneof two node IDs included in the branch, whereas the “node ID₂” is a nodeID of the other of the two node IDs included in the branch. A branchpositioned at an end, such as an SS and a load facility, may have one ofthe node ID₁ and the node ID₂ alone. The node ID₁ out of the node ID₁and the node ID₂, for example, is a node ID of a connection closer tothe primary side than the node ID₂, that is, closer to the SS. The nodeID₂ is a node ID of a connection closer to the secondary side than thenode ID₁, that is, closer to the load facility. The “facility ID” isidentification information for identifying a facility, and the branchtable 16 b stores therein the facility ID of a unit or a span. The“open-close section” indicates an open-close state of a switch. When thebranch is a switch, one of an “open state” and a “closed state” is setin the open-close section, whereas when the branch is not a switch, a“blank” is set.

The information stored in the branch table 16 b is acquired from otherexisting systems, such as a distribution facility management system anda distribution automation system. A branch is, for example, extractedfrom information on facilities of a low-voltage system acquired from thedistribution facility management system or information on facilities ofa high-voltage system acquired from the distribution automation system.Subsequently, the branch is registered in the branch table 16 b in amanner associated with the node included in the branch.

FIG. 8 is an example diagram of the branch table 16 b. It is indicatedthat the branch of a branch ID “BR0001” illustrated in FIG. 8 is ahigh-voltage wire of a facility ID “SP0001” defined by a node ID₁“SS0001N01” and a node ID₂ “PO0001N01”, for example. It is alsoindicated that the branch of a branch ID “BR0002” illustrated in FIG. 8is a switch of a facility ID “PO000101” defined by a node ID₁“PO0001N01” and a node ID₂ “PO0001N02”. Because “1” is set in theopen-close section of the branch of the branch ID “BR0002”, it isindicated that the switch is in the closed state. A value “0” set in theopen-close section illustrated in FIG. 8 indicates that the switch is inthe open state, and a blank in the open-close section indicates that thefacility is not a switch. The switch in the closed state allowselectricity to pass therethrough, whereas the switch in the open statedoes not allow electricity to pass therethrough.

The distribution system information 17, the load information 18, and thepower loss amount information 20 out of the information stored in thestorage unit 13 other than the positional information 14, the facilityinformation 15, and the electrical connection information 16 will bedescribed later in explanations of functional units that generate,acquire, and use these pieces of information.

The control unit 19 includes an internal memory that stores therein acomputer program and control data defining various types of processingprocedures and performs various types of processing with these pieces ofdata. As illustrated in FIG. 1, the control unit 19 includes a retrievalunit 19 a, an associating unit 19 b, an acquiring unit 19 c, a firstcalculating unit 19 d, a second calculating unit 19 e, a totalizing unit19 f, and a display control unit 19 g.

The retrieval unit 19 a is a processing unit that retrieves a branch.The retrieval unit 19 a refers to the electrical connection information16 to search for a yet-to-be-searched-for node out of nodes included ina combination of nodes using a predetermined node as an origin, therebyretrieving a branch corresponding to the combination.

In one aspect, when a browsing request for distribution systeminformation is received via the client terminal 30 or a predeterminedperiod has passed since the end of the previous processing, theretrieval unit 19 a starts processing. The retrieval unit 19 a retrievesa position ID whose position type is a substation “SS” out of theposition IDs stored in the location table 14 a. The retrieval unit 19 aregisters the position ID of SS retrieved from the location table 14 ain a search list stored in an internal memory, which is not illustrated.The search list registers therein a yet-to-be-searched-for node andbranch found in the searching as needed besides the position ID of SS tobe searched for. While the retrieval unit 19 a retrieves the position IDof SS from the location table 14 a in this example, the retrieval unit19 a may retrieve a node ID whose character string begins with “SS” outof the node IDs stored in the node table 16 a and the branch table 16 b.

Subsequently, the retrieval unit 19 a selects one position ID of SSregistered in the search list. The retrieval unit 19 a retrieves a nodecorresponding to the selected position ID of SS from the nodes stored inthe node table 16 a. The retrieval unit 19 a then registers the recordof the node retrieved from the node table 16 a in the current node table17 a stored in the storage unit 13 as the distribution systeminformation 17. The retrieval unit 19 a also registers the noderetrieved from the node table 16 a in the search list. In the case of SShaving a plurality of SS banks, even if the retrieval is performed withone position ID, records of a plurality of nodes are retrieved.

Subsequently, the retrieval unit 19 a selects one node registered in thesearch list. The retrieval unit 19 a retrieves a combination of node IDsincluding the selected node from the branches stored in the branch table16 b, that is, a record of a branch including a combination of a nodeID₁ and a node ID₂. The retrieval unit 19 a then registers the record ofthe branch retrieved from the branch table 16 b in the current branchtable 17 b stored in the storage unit 13 as the distribution systeminformation 17. The retrieval unit 19 a also registers the branchretrieved from the branch table 16 b in the search list. The informationregistered in the search list simply needs to be information foridentifying the branch. At least one of the branch ID and the facilityID may be registered, for example.

Subsequently, the retrieval unit 19 a selects one branch registered inthe search list. The retrieval unit 19 a retrieves attribute informationcorresponding to the facility ID of the selected branch from the spantable 15 b. If the branch is a span, the retrieval unit 19 a canretrieve the attribute information from the span table 15 b. If thebranch is a unit, the retrieval unit 19 a fails to retrieve theattribute information. If the retrieval unit 19 a fails to retrieve theattribute information from the span table 15 b, the retrieval unit 19 aretrieves the attribute information corresponding to the facility ID ofthe selected branch from the unit table 15 a.

If a second node making a pair with the node used for the searching inthe combination of nodes is not a blank, the retrieval unit 19 adetermines whether the branch is a switch. If the branch is a switch,the retrieval unit 19 a determines whether the switch is in the closedstate, that is, whether “1” is set in the open-close section. If theswitch is in the closed state, the retrieval unit 19 a retrieves therecord of the second node from the node table 16 a and registers therecord in the current node table 17 a in the distribution systeminformation 17. The retrieval unit 19 a adds the second node to thesearch list as a yet-to-be-searched-for node.

The retrieval unit 19 a repeats the processing from the selection of ayet-to-be-searched-for branch until the search for all the branchesregistered in the search list ends. If all the branches registered inthe search list are searched for, the retrieval unit 19 a repeats theprocessing from the selection of a yet-to-be-searched-for node until thesearch for all the nodes registered in the search list ends.Subsequently, the retrieval unit 19 a repeats the processing from theselection of a yet-to-be-searched-for position ID of SS until the searchfor all the position ID of SS registered in the search list ends.

The associating unit 19 b is a processing unit that associates acombination of connections on which searching is performed and afacility obtained as a result of retrieval with attribute informationcorresponding to the facility obtained as the result of the retrievalout of the attribute information included in the facility information15. In one aspect, the associating unit 19 b associates a record of abranch on which searching is performed with attribute information on thebranch retrieved from tine span table 15 b or the unit fable 15 a. Theassociating unit 19 b, for example, registers attribute information on abranch in a manner associated with the facility ID or the branch ID ofthe branch used to search the span table 15 b or the unit table 15 a outof the records stored in the current branch table 17 b. The associatingunit 19 b may retrieve a position ID corresponding to the facility ID ofthe branch from the unit table 15 a or the span table 15 b and furtherassociate the position ID with the record of the branch.

The following specifically describes the contents of the processingperformed by the retrieval unit 19 a and the associating unit 19 b withreference to the tables illustrated in FIG. 4 to FIG. 8. The position ID“SS0001” whose position type is a substation “SS” is retrieved from theposition IDs stored in the location table 14 a illustrated in FIG. 4.The position ID “SS0001” of SS retrieved from the location table 14 a isregistered in the search list. Because no other position ID than theposition ID “SS0001” of SS is registered in the search list, theposition ID “SS0001” is selected. In response to this, the node ID“SS0001N01” corresponding to the selected position ID “SS0001” of SS isretrieved from the nodes stored in the node table 16 a illustrated inFIG. 7. Subsequently, the record of the node ID “SS0001N01” retrievedfrom the node table 16 a is registered in the current node table 17 a.The node ID “SS0001N01” retrieved from the node table 16 a is alsoregistered in the search list. Because no other node ID than the node ID“SS0001N01” is registered in the search list, the node ID “SS0001N01” isselected.

A branch of the facility ID “SP0001” associated with a combination ofthe node ID₁ “SS0001N01” and the node ID₂ “PO0001N01” including theselected node ID “SS0001N01” is retrieved from the branches stored inthe branch table 16 b illustrated in FIG. 8. Subsequently, the record ofthe branch of the facility ID “SP0001” retrieved from the branch table16 b is registered in the current branch table 17 b. The facility ID“SP0001” retrieved from the branch table 16 b is also registered in thesearch list. Because no other facility ID than the facility ID “SP0001”is registered in the search list, the facility ID “SP0001” is selected.

As a result, attribute information “a span length of 21 m, a resistanceR_(H1), and a reactance X_(H1)” of a span corresponding to the selectedfacility ID “SP0001” is retrieved from the span table 15 b illustratedin FIG. 6. In this example, the attribute information on the span isretrieved. In the case of a facility ID whose character string beginswith characters other than “SP”, no attribute information is retrievedfrom the span table 15 b, but attribute information on a unit isretrieved from the unit table 15 a illustrated in FIG. 5.

Based on the acquired attribute information “a span length of 21 m, aresistance of 220 Ω/m, and a reactance of 150 Ω/m”, a resistance of 4621(220×21) Ω and a reactance of 3150 (150×21) Ω are registered in thecurrent branch table 17 b in a manner associated with the facility ID“SP0001”.

In the combination of the node ID₁ “SS0001N01” and the node ID₂“PO0001N01”, “PO0001N01” is set to a second node ID making a pair withthe node ID “SS0001N01” used for the searching. Because the second nodeID is not a blank, it is determined whether the branch of the facilityID “SP0001” is a switch. Because the branch of the facility ID “SP0001”has a blank in the open-close section, the branch is not a switch. Thus,the record of the second node ID “PO001N01” is retrieved from the nodetable 16 a and then is registered in the current node table 17 a in thedistribution system information 17. The second node ID “PO0001N01” isadded to the search list as a yet-to-be-searched-for node.

When the second node ID “PO0001N01” is registered in the search list asa yet-to-be searched for node, no other node ID than the node ID“PO0001N01” is registered. Thus, the node ID “PO0001N01” is selected,and the searching is continued.

In this example, the second node ID is not a blank. If the second nodeID is a blank, a yet-to-be-searched-for branch registered in the searchlist is searched for. If no yet-to-be-searched-for branch is present, ayet-to-be-searched-for node is searched for. If noyet-to-be-searched-for position ID of SS is present, the searching isterminated. In this example, the branch is not a switch. If the branchis a switch and the switch is not in the closed state, neither retrievalof the second node ID nor addition of the second node to the search listis performed. If the switch is in the open state and retrieval of thesecond node ID and addition of the second node to the search list areperformed, a different distribution system not electrically connected iserroneously registered in the current node table 17 a and the currentbranch table 17 b.

The searching described above retrieves nodes of distribution systemswhose facilities are electrically connected when the searching isperformed on the branches registered in the node table 16 a, therebygenerating the current node table 17 a. The searching also retrievesbranches of distribution systems electrically connected when thesearching is performed on the branches registered in the branch table 16b and attribute information corresponding to the branches. Thisgenerates the current branch table 17 b in which the branches and theattribute information are associated with each other. In the descriptionbelow, the distribution systems whose facilities are electricallyconnected when the searching is performed may be referred to as a“current system”.

The distribution system information 17 includes the current node table17 a and the current branch table 17 b generated as described above, andis registered in the storage unit 13. FIG. 9 is an example diagram ofthe current node table 17 a. FIG. 10 is an example diagram of thecurrent branch table 17 b. FIG. 9 and FIG. 10 illustrate the currentnode table 17 a and the current branch table 17 b, respectively. Thesetables 17 a and 17 b are generated based on the tables illustrated inFIG. 4 to FIG. 8 using the node ID “SS0001N01” as an origin.

Nodes “LL0001N01”, “LL0002N01”, “LL0003N01”, “LL0004N01”, “LL0005N01”,“LL0006N01”, “LL0007N01”, and “LL0008N01” are connections of the loadfacility of the consumer and the facility of the distribution system. Asillustrated in FIG. 9, the records of these nodes out of the records inthe current node table 17 a have the amount of power consumptionmeasured by a meter, such as a smart meter, as an example of theattribute information. The amount of power consumption includes “activepower” consumed by the load facilities and “reactive power” not consumedby the load facilities. The reactive power is also referred to as delayreactive power. The amount of power consumption (active) and the amountof power consumption (reactive) are referred to in calculation of avoltage at each node.

As illustrated in FIG. 10, records of facilities serving as a switch inthe branch out of the records in the current branch table 17 b each havethe value of the open-close section registered in the branch table 16 b.The switches of the branch IDs “BR0002”, “BR0006”, and “BR0019”, forexample, have “1” in the open-close section. This indicates that theswitch is in the closed state and establishes electrical continuity.FIG. 10 illustrates the switches having “1” in the open-close section,for example. By contrast, “0” set in the open-close section of a switchindicates that the switch is in the open state and breaks electricalcontinuity. The records in the current branch table 17 b each have areactance X and a resistance R as an example of the attributeinformation. Facilities serving as a unit in the branch, such as aswitch and a transformer, each have the reactance X and the resistance Rregistered in the unit table 15 a without any change as the attributeinformation. By contrast, facilities serving as a span in the brancheach have a value obtained by multiplying the reactance per unit by thespan length registered in the span table 15 b as the reactance X andhave a value obtained by multiplying the resistance per unit by the spanlength as the resistance R. The reactance X and the resistance R of theunit and the span are referred to in calculation of a voltage at eachnode.

In this example, various types of parameters are used to calculate avoltage, including the amount of power consumption (active), the amountof power consumption (reactive), the resistance, and the reactance. Byadding an item of a connection phase to which the transformer isconnected to one of the current node table 17 a and the current branchtable 17 b, it is possible to calculate a voltage more precisely. In thecase of an electric wire serving as a single phase three-wire, forexample, a first transformer connected to the wire on the pole isreferred to as a “first connection phase”, a second transformer isreferred to as a “second connection phase”, and a third transformer isreferred to as a “third connection phase”. When a transformer isconnected to the first and the second electric wires of the threeelectric wires, “A” is registered. When a transformer is connected tothe second and the third electric wires, “B” is registered. When atransformer is connected to the first and the third electric wires, “C”is registered.

The distribution system information 17 is generated based on the currentnode table 17 a illustrated in FIG. 9 and the current branch table 17 billustrated in FIG. 10, and has a graph structure of the distributionsystem illustrated in FIG. 11 and FIG. 12. FIG. 11 and FIG. 12 areexample diagrams of the graph structure of the current system. Thecurrent system illustrated in FIG. 11 and FIG. 12 includes the node ofthe node ID “SS0001N01” serving as a connection of an SS bank and ahigh-voltage wire of the facility ID “SP0001” at a root (a first layer)of the hierarchical structure. The current system further includes pathsextending from the root to eight load facilities of facility IDs“LL000101”, “LL000201”, “LL000301”, “LL000401”, “LL000501”, “LL000601”,“LL000701”, and “LL000801” serving as ends. The number of layers fromthe SS bank to the load facility of the facility ID “LL000801” is 10,and thus the load facility “LL000801” is positioned at the shallowestlayer. The number of layers from the SS bank to the load facilities ofthe facility IDs “LL000201”, “LL000301”, and “LL000401” is 19, and thusthe load facilities “LL000201”, “LL000301”, and “LL000401” arepositioned at the deepest layer. Generating the distribution systeminformation 17 makes it possible to grasp the electrical connection ofthe current system not in rough units, such as a high-voltage system anda low-voltage system, but in units of facilities, more specifically, inunits of connections between the facilities in a minute manner.

Referring back to FIG. 1, the acquiring unit 19 c is a processing unitthat acquires load information on a power consumption facility. Theacquiring unit 19 c, for example, acquires the amount of powerconsumption of the smart meter 50 as the load information on the powerconsumption facility. An aspect of the acquiring unit 19 c acquires theamount of power consumption updated by the smart meter 50 connected tothe load facility of each consumer. The acquiring unit 19 c thenadditionally registers a record in which the facility ID of the loadfacility to which the smart meter 50 is connected, the date and time ofupdating, and the amount of power consumption are associated with oneanother to a load table 18 a in the load information 18. An assumptionis made that each smart meter 50 updates the amount of power consumptionevery predetermined period (e.g., every 30 minutes). The load table 18 astores therein the load information on the power consumption facilityacquired every predetermined period. The load table 18 a, for example,registers therein the record on a cycle of a time corresponding to thesum of an interval of meter reading to cause the smart meter 50 totransmit the reading result of the amount of power consumption and atransmission delay time between the smart meter 50 and the losscalculating device 10 for each smart meter 50.

The following describes an example of the load information 18 stored inthe storage unit 13. The load information 18 may have the load table 18a in which items including the facility ID, a date, time, and the amountof power consumption are associated with one another. FIG. 13 is anexample diagram of the load table 18 a. FIG. 13 indicates that the smartmeter 50 connected to a load facility of a facility ID “LL1” uploads anamount of power consumption U11 at 14:40:18 on Sep. 5, 2012 and anamount of power consumption U12 at 15:10:19. FIG. 13 illustratesexamples of load facilities independent of the facilities illustrated inthe unit table 15 a in FIG. 5 for convenience of explanation.

The first calculating unit 19 d is a processing unit that calculates aload current of each distribution facility. The first calculating unit19 d calculates a voltage at each current node. In one aspect, the firstcalculating unit 19 d starts processing for calculating a voltage ateach current node from a current node included in a substation toward acurrent node included in a load facility side in each distributionsystem, when a history relating to the amount of power consumptionuploaded by the smart meter 50 is updated, in the load table 18 a.

Specifically, the first calculating unit 19 d reads information used tocalculate the voltage from the current branch table 17 b. The firstcalculating unit 19 d acquires a voltage of electric power transmittedfrom the substation, a voltage ratio of a transformer, and a resistanceand a reactance of an electric wire, for example. In the descriptionbelow, the voltage of the electric power transmitted from the substationmay be referred to as a “sending voltage”. The first calculating unit 19d further reads the amount of power consumption in the load facility ofeach consumer from the load table 18 a. When the amount of powergeneration exceeds the amount of power consumption, for example, theamount of power consumption may possibly have a negative value. When theamount of power consumption has a negative value, a reverse power flowoccurs. The reverse power flow is a phenomenon of electric powergenerated by a power generation facility of the consumer flowing fromload facility side toward the distribution system. In this case, theelectric power supplier purchases the electric power from the consumer.

The first calculating unit 19 d calculates the voltage at each currentnode using the parameters, such as the sending voltage of thesubstation, the voltage ratio of the transformer, the resistance and thereactance of the electric wire, and the amount of power consumption ofthe load facility. Examples of the method for calculating the voltageinclude a known algorithm, such as backward-forward sweep (BFS) and aNewton-Raphson method. If the BFS is employed, for example, sequentialcalculation from load facilities (to substation) and modification fromthe substation are alternately made using the characteristics of thedistribution system being radially arranged, thereby calculating thevoltage at each current node. This operation calculates the voltage ateach current node of the end included in load facilities of customers.

The first calculating unit 19 d then calculates a load current of eachdistribution facility. The first calculating unit 19 d, for example,calculates an electric current flowing through a distribution facility,such as a high-voltage wire, a transformer, a low-voltage wire, and alead-in wire, based on a voltage at a current node corresponding to thedistribution facility and a resistance and a reactance of thedistribution facility.

The second calculating unit 19 e is a processing unit that calculatesthe amount of power loss in each distribution facility. The secondcalculating unit 19 e, for example, calculates the amount of power lossin each distribution facility based on the load information 18 of eachdistribution facility and the load current of each distribution facilitycalculated by the first calculating unit 19 d. The second calculatingunit 19 e, for example, multiplies the resistance R of a distributionfacility by the square of an electric current value I of an electriccurrent flowing through the distribution facility (R×I²), therebyderiving the amount of power loss in the distribution facility. Thesecond calculating unit 19 e makes the same calculation in the case of areverse power flow, for example.

FIG. 14 and FIG. 15 are example diagrams of the amount of power loss inthe current system. FIG. 14 and FIG. 15 illustrate the amount of powerloss in each distribution facility of the distribution systemillustrated in FIG. 11 and FIG. 12, respectively, as a distributionloss. The example in FIG. 14 indicates that the high-voltage wire of thefacility ID “SP0001” generates power loss of 0.0087 Wh. The example inFIG. 15 indicates that the lead-in wire of the facility ID “SP0015”generates power loss of 0.2183 Wh. Thus, the loss calculating device 10can grasp the power loss in units of distribution facilities.

The load information on the power consumption facility is acquired everypredetermined period. The first calculating unit 19 d and the secondcalculating unit 19 e calculate, every predetermined period, the amountof power loss in each distribution facility using the load informationon the power consumption facilities acquired in the predeterminedperiod. In one aspect, the first calculating unit 19 d and the secondcalculating unit 19 e start the processing every time the predeterminedperiod has passed since the end of the previous calculation of theamount of power loss, thereby calculating the amount of power loss ineach distribution facility. The second calculating unit 19 e stores theamount of power loss calculated for each distribution facility and dateand time information on the predetermined period for the calculation inthe storage unit 13 as the power loss amount information 20.

The totalizing unit 19 f is a processing unit that performs varioustypes of totalization of the amount of power loss in each predeterminedperiod stored in the power loss amount information 20. When a displaycondition is specified on a specification screen used to specify thedisplay condition of power loss, which will be described later, forexample, the totalizing unit 19 f totalizes the amount of power lossunder the specified display condition.

When any one of the nodes is specified, for example, the totalizing unit19 f totalizes the amount of power loss in each predetermined period indistribution facilities positioned at layers of and below the specifiednode every predetermined period. When totalization in units of the typesof tine distribution facilities is specified, for example, thetotalizing unit 19 f totalizes the amount of power loss in eachpredetermined period in each distribution facility in units of thepredetermined period and the types of the distribution facilities. Inone aspect, the totalizing unit 19 f totalizes the amount of power lossin each predetermined period in units of the types of the distributionfacilities, such as the high-voltage wires, the transformers, thelow-voltage wires, and the lead-in wires. When calculation of the sum ofthe amount oil power loss in each predetermined period is specified, forexample, the totalizing unit 19 f calculates the sum of the amount ofpower loss in each predetermined period. The totalizing unit 19 f, forexample, calculates the sum of the amount of power loss in apredetermined totalization period longer than the predetermined periodin units of the types of the distribution facilities. In one aspect, thetotalizing unit 19 f calculates the sum of the amount of power loss perday in units of the types of the distribution facilities, such as thehigh-voltage wires, the transformers, the low-voltage wires, and thelead-in wires.

The display control unit 19 g is a processing unit that performs displaycontrol on the client terminal 30. The display control unit 19 g, forexample, displays the specification screen used to specify various typesof display conditions under which the power loss is displayed on theclient terminal 30. The display control unit 19 g displays the amount ofpower loss on the client terminal 30 according to the conditionspecified on the specification screen.

When a certain period and a distribution facility for which the amountof power loss is to be displayed are specified, for example, the displaycontrol unit 19 g reads the amount of power loss in the specified periodand in the specified distribution facility from the power loss amountinformation 20. The display control unit 19 g then displays the amountof power loss on the client terminal 30. When the client terminal 30instructs display of the amount of power loss while specifying a node,for example, the display control unit 19 g displays the amount of powerloss in each predetermined period in nodes positioned at layers of andbelow the specified node, which the amount of power loss is totalized bythe totalizing unit 19 f. In one aspect, the display control unit 19 gdisplays the amount of power loss in each predetermined period in thedistribution facilities on a graph.

FIG. 16 is an example graph of the amount of power loss in eachpredetermined period in specified facilities. The example in FIG. 16illustrates the amount of power loss in each predetermined period in thefacilities of the facility IDs “PO0007 01”, “PO0012 01”, and “PO001501”. By displaying the amount of power loss in each predetermined periodon a graph, it is possible to grasp a temporal change in the amount ofpower loss and a peak and the state of the amount of power loss.

When totalization in units of the types of the distribution facilitiesis specified, for example, the display control unit 19 g displays theamount of power loss in each predetermined period totalized by thetotalizing unit 19 f in units of the types of the distributionfacilities. An aspect of the display control unit 19 g displays theamount of power loss in each predetermined period in units of the typesof the distribution facilities, such as the high-voltage wires, thetransformers, the low-voltage wires, and the lead-in wires, on a graph.

FIG. 17 is an example graph of the amount of power loss in eachpredetermined period in units of the types of the distributionfacilities. The example in FIG. 17 illustrates the amount of power lossin each predetermined period in the high-voltage wires, thetransformers, the low-voltage wires, and the lead-in wires. Bydisplaying the amount of power loss in each predetermined period inunits of the types of the distribution facilities, it is possible tograsp a temporal change in the amount of power loss in units of thetypes of the distribution facilities.

When calculation of the sum of the amount of power loss in eachpredetermined period is specified, for example, the display control unit19 g displays the sum of the amount of power loss in the totalizationperiod, which the amount of power loss is totalized by the totalizingunit 19 f in units of the types of the distribution facilities. In oneaspect, the display control unit 19 g displays the sum of the amount ofpower loss per day in units of the types of the distribution facilities,such as the high-voltage wires, the transformers, the low-voltage wires,and the lead-in wires, on a pie chart.

FIG. 18 is an example pie chart of the amount of power loss per day inunits of the types of the distribution facilities. The example in FIG.18 illustrates the amount of power loss in each predetermined period inthe high-voltage wires, the transformers, the low-voltage wires, and thelead-in wires in total. By displaying the amount of power loss in eachpredetermined period in units of the types of the distributionfacilities in total, it is possible to grasp which type of thedistribution facility has a large amount of power loss.

While the display control unit 19 g displays various types ofinformation on the client terminal 30 in the present embodiment, thedisplay control unit 19 g may display the information on a display unitincluded in the loss calculating device 10 and other devices.

The control unit 19 may be various types of circuits, includingintegrated circuits and electronic circuits. A part of the functionalunits included in the control unit 19 may be other integrated circuitsor electronic circuits. Examples of the integrated circuits include anapplication specific integrated circuit (ASIC). Examples of theelectronic circuits include a central processing unit (CPU) and a microprocessing unit (MPU).

Procedure of Processing

The following describes the procedure of processing performed by theloss calculating device 10 according to the present embodiment. Theexplanation will be made of distribution management processing first andthen loss calculation processing performed by the loss calculatingdevice 10.

(1) Distribution Management Processing

FIG. 19 and FIG. 20 are flowcharts of the distribution managementprocessing according to the first embodiment. The distributionmanagement processing is started at a predetermined timing,specifically, when a distribution facility of the distribution system isinstalled or when a browsing request for the amount of power loss isreceived via the client terminal 30, for example.

As illustrated in FIG. 19, the retrieval unit 19 a retrieves a positionID whose position type is a substation “SS” out of the position IDsstored in the location table 14 a (Step S101). The retrieval unit 19 aregisters the position ID of SS retrieved from the location table 14 ain the search list (Step S102).

Subsequently, the retrieval unit 19 a selects one position ID of SSregistered in the search list (Step S103). The retrieval unit 19 aretrieves a node corresponding to the selected position ID of SS fromthe nodes stored in the node table 16 a (Step S104).

The retrieval unit 19 a registers the record of the node retrieved fromthe node table 16 a in the current node table 17 a stored in the storageunit 13 as the distribution system information 17 (Step S105). Theretrieval unit 19 a also registers the node retrieved from the nodetable 16 a in the search list (Step S106).

Subsequently, the retrieval unit 19 a selects one node registered in thesearch list (Step S107). The retrieval unit 19 a retrieves a combinationof node IDs including the node selected at Step S107 from the branchesstored in the branch table 16 b, that is, a record of a branch includinga combination of a node ID₁ and a node ID₂ (Step S108).

The retrieval unit 19 a registers the record of the branch retrieved atStep S108 in the current branch table 17 b (Step S109). The retrievalunit 19 a also registers the branch retrieved at Step S108 in the searchlist (Step S110). Subsequently, the retrieval unit 19 a selects onebranch registered in the search list (Step S111).

The retrieval unit 19 a retrieves attribute information corresponding tothe facility ID of the branch selected at Step S111 from the span table15 b as illustrated in FIG. 20 (Step S112). If the retrieval unit 19 afails to retrieve the attribute information from the span table 15 b, orif there is no hit for the attribute information (No at Step S113), theretrieval unit 19 a performs the following processing.

Specifically, the retrieval unit 19 a retrieves the attributeinformation corresponding to the facility ID of the branch selected atStep S111 from the unit table 15 a (Step S114). If the retrieval unit 19a can retrieve the attribute information from the span table 15 b (Yesat Step S113), the processing at Step S114 is skipped, and the processproceeds to Step S115.

The associating unit 19 b registers the attribute information on thebranch in a manner associated with the record of the branch used tosearch the span table 15 b or the unit table 15 a out of the recordsstored in the current branch table 17 b (Step S115).

The retrieval unit 19 a determines whether a second node making a pairwith the node used for the searching at Step S108 in the combination ofnodes included in the branch retrieved at Step S108 is a blank (StepS116).

If the second node is not a blank (Yes at Step S116), the retrieval unit19 a determines whether the branch is a switch (Step S117). If thebranch is a switch (Yes at Step S117), the retrieval unit 19 adetermines whether the switch is in the closed state, that is, whetherthe switch is in an ON state (Step S118).

If the switch is in the ON state (Yes at Step S118), the retrieval unit19 a retrieves the record of the second node from the node table 16 aand registers the record in the current node table 17 a in thedistribution system information 17 (Step S119). The retrieval unit 19 aadds the second node to the search list as a yet-to-be-searched-for node(Step S120).

If the branch is not a switch (No at step S117), the retrieval unit 19 aalso retrieves the record of the second node from the node table 15 aand registers the record in the current node table 17 a in thedistribution system information 17 (Step S119). The retrieval unit 19 aadds the second node to the search list as a yet-to-be-searched-for node(Step S120).

By contrast, if the second node is a blank or the switch is in an OFFstate (No at Step S116 or No at Step S118), the process proceeds to StepS121.

Subsequently, the retrieval unit 19 a determines whether all thebranches registered in the search list are searched for (Step S121). Ifall the branches registered in the search list are not searched for (Noat Step S121), a yet-to-be-searched-for branch is selected (Step S111),and the processing from Step S112 to Step S120 is repeated.

If all the branches registered in the search list are searched for (Yesat Step S121), the retrieval unit 19 a determines whether all the nodesregistered in the search list are searched for (Step S122). If all thenodes registered in the search list are not searched for (No at StepS122), a yet-to-be-searched-for node is selected (Step S107), and theprocessing from Step S108 to Step S121 is repeated.

If all the nodes registered in the search list are searched for (Yes atStep S122), the retrieval unit 19 a determines whether all the positionIDs of SS registered in the search list are searched for (Step S123). Ifall the position IDs of SS registered in the search list are notsearched for (No at Step S123), a yet-to-be-searched-for position ID ofSS is selected (Step S103), and the processing from Step S104 to StepS122 is repeated.

If all the position IDs of SS registered in the search list are searchedfor (Yes at Step S123), the first calculating unit 19 d calculates aload current of each distribution facility (Step S124). The firstcalculating unit 19 d, for example, calculates a voltage at each currentnode toward a current node using a sending voltage of electric powertransmitted from the substation and the amount of power consumption inthe load facility of each consumer read from the load table 18 a. Thus,the first calculating unit 19 d calculates the load current of eachdistribution facility. The second calculating unit 19 e calculates theamount of power loss in each distribution facility based on the loadinformation on each distribution facility and the load currentcalculated for each distribution facility (Step S125). The secondcalculating unit 19 e stores the amount of power loss calculated foreach distribution facility and date and time information on thepredetermined period for the calculation in the storage unit 13 as thepower loss amount information 20 (Step S126). The processing is thenterminated.

(2) Loss Calculation Processing

FIG. 21 is a flowchart of the loss calculation processing according tothe first embodiment. The display control processing is performed when adisplay condition is specified on a specification screen used to specifythe display condition of power loss displayed on the client terminal 30,for example.

As illustrated in FIG. 21, the totalizing unit 19 f determines whether acertain period and a distribution facility for which the amount of powerloss is to be displayed are specified on the specification screen (StepS150). If a certain period and a distribution facility for which theamount of power loss is to be displayed are specified (Yes at StepS150), the display control unit 19 g reads the amount of power loss inthe specified period and in the specified distribution facility from thepower loss amount information 20, and displays the amount of power losson the client terminal 30 (Step S151). The processing is thenterminated.

By contrast, if no certain period or no distribution facility for whichthe amount of power loss is to be displayed is specified (No at StepS150), the totalizing unit 19 f determines whether display of the amountof power loss is instructed with a specified node (Step S152). Ifdisplay of the amount of power loss is instructed with a specified node(Yes at Step S152), the totalizing unit 19 f totalizes the amount ofpower loss in each predetermined period in the distribution facilitiespositioned at layers of and below the specified node every predeterminedperiod (Step S153). The display control unit 19 g displays the amount ofpower loss totalized every predetermined period for the specified node(Step S154). The processing is then terminated.

By contrast, if display of the amount of power loss is not instructedwith a specified node (No at Step S152), the totalizing unit 19 fdetermines whether totalization in units of the types of thedistribution facilities is specified (Step S155). If the totalization inunits of the types of the distribution facilities is specified (Yes atStep S155), the totalizing unit 19 f totalizes the amount of power lossin each predetermined period in each distribution facility in units ofthe predetermined period and the types of the distribution facilities(Step S156). The display control unit 19 g displays the amount of powerloss in each predetermined period totalized in units of the types of thedistribution facilities (Step S157). The processing is then terminated.

By contrast, if the totalization in units of the types of thedistribution facilities is not specified (No at Step S155), thetotalizing unit 19 f determines whether calculation of the sum of theamount of power loss in each predetermined period is specified (Step atS158). If calculation of the sum of the amount of power loss in eachpredetermined period is specified (Yes at Step at S158), the totalizingunit 19 f calculates the sum of the amount of power loss in apredetermined totalization period in units of the types of thedistribution facilities (Step S159). The display control unit 19 gdisplays the sum of the amount of power loss in the totalization periodtotalized in units of the types of the distribution facilities (StepS160). The processing is then terminated.

Advantageous Effects of the First Embodiment

As described above, the loss calculating device 10 according to thepresent embodiment calculates a load current of each distributionfacility based on a sending voltage in a power source facility and loadinformation on power consumption facilities in an electrical circuitincluding the power source facility, the distribution facilities, andthe power consumption facilities connected to one another to form theelectrical circuit. Based on the load current calculated for eachdistribution facility, the loss calculating device 10 calculates theamount of power loss in each distribution facility. Thus, the losscalculating device 10 according to the present embodiment can grasp thedistribution loss in each distribution facility.

The loss calculating device 10 acquires the load information on thepower consumption facilities every predetermined period. The losscalculating device 10 calculates the load current of each distributionfacility in each predetermined period based on the sending voltage inthe power source facility and the load information on the powerconsumption facilities acquired every predetermined period. The losscalculating device 10 uses the load current in each predetermined periodcalculated for each distribution facility, thereby calculating theamount of power loss in each predetermined period in each distributionfacility. Thus, the loss calculating device 10 according to the presentembodiment can grasp the distribution loss in each predetermined periodin each distribution facility.

The loss calculating device 10 totalizes the amount of power loss ineach predetermined period calculated for each distribution facility inunits of the predetermined period and the types of the distributionfacilities. The loss calculating device 10 displays the amount of powerloss totalized in units of the predetermined period and the types of thedistribution facilities. Thus, the loss calculating device 10 accordingto the present embodiment can grasp the distribution loss in units ofthe predetermined period and the types of the distribution facilities.

The loss calculating device 10 calculates the sum of the amount of powerloss in each predetermined period calculated for each distributionfacility in units of the types of the distribution facilities. The losscalculating device 10 displays the sum of the amount of power losscalculated in units of the types of the distribution facilities. Thus,the loss calculating device 10 according to the present embodiment cangrasp the sum of the distribution loss in units of the types of thedistribution facilities.

[b] Second Embodiment

Configuration of a Loss Calculating Device

A second embodiment according to the present invention will bedescribed. FIG. 22 is a block diagram of a functional configuration of aloss calculating device 10 according to the second embodiment. Theconfiguration of the loss calculating device 10 according to the secondembodiment is nearly the same as that of the first embodiment.Components similar to those of the first embodiment are denoted by likereference numerals, and the explanation will be mainly made of differentparts.

As illustrated in FIG. 22, a storage unit 13 of the loss calculatingdevice 10 according to the second embodiment stores therein unit priceinformation 25 and facility performance information 26.

The unit price information 25 is data storing therein a unit price usedto convert electric power into an amount of money. The unit priceinformation 25, for example, stores therein a unit price perpredetermined unit of electric power.

FIG. 23 is an example diagram of the unit price information 25. The unitprice information 25 illustrated in FIG. 23 stores therein 18 yen as aunit price per 1 kWh, for example.

The facility performance information 26 is data storing therein varioustypes of information on various types of distribution facilities. Thefacility performance information 26, for example, stores thereininformation on the performance of a distribution facility and the unitprice of the distribution facility.

FIG. 24 is an example diagram of the facility performance information26. The facility performance information 26 illustrated in FIG. 24stores therein information on transformers having different transformercapacities as distribution facilities. The facility performanceinformation 26 indicates that the unit price of a transformer of 30 kVAis 160,000 yen and that the unit price of a transformer of 10 kVA is120,000 yen, for example. The facility performance information 26 mayalso store therein various types of information on electricalcharacteristics and performance of the facilities. The facilityperformance information 26 may store therein the capacity of thetransformers, for example.

A second calculating unit 19 e calculates a loss price due to the amountof power loss in each distribution facility based on the amount of powerloss in each distribution facility. The second calculating unit 19 e,for example, multiplies the amount of power loss by the unit price ofelectric power stored in the unit price information 25 for eachdistribution facility, thereby deriving the loss price.

A display control unit 19 g displays the calculated loss price whendisplaying the amount of power loss. The display control unit 19 g, forexample, displays the amount of power loss in each predetermined periodin units of the types of the distribution facilities, such ashigh-voltage wires, transformers, low-voltage wires, and lead-in wires,as the loss price.

FIG. 25 is an example graph of the loss price in each predeterminedperiod in units of the types of the distribution facilities. The examplein FIG. 25 illustrates the loss price in each predetermined period inthe high-voltage wires, the transformers, the low-voltage wires, and thelead-in wires. This makes it possible to grasp the loss price due to theamount of power loss in units of the types of the distributionfacilities.

A control unit 19 includes a simulation unit 19 h.

The display control unit 19 g displays a simulation instruction screenused to instruct execution of a simulation when a distribution facilityis replaced on the client terminal 30. The simulation instruction screenenables specification of a distribution facility to be replaced based onthe facility performance information 26.

When replacement of a distribution facility is specified on thesimulation instruction screen, the simulation unit 19 h runs varioustypes of simulations relating to the distribution system with thespecified distribution facility. When replacement of a distributionfacility forming a node or a branch stored in a current node table 17 aor a current branch table 17 b in distribution system information 17 isspecified, for example, the simulation unit 19 h runs a simulation ofthe replacement. An assumption is made that an instruction to replace atransformer of 30 kVA with a transformer of 10 kVA in the distributionsystem is issued, for example. The simulation unit 19 h reads from thefacility performance information 26, the performance and the unit priceof the distribution facilities before and after the replacement. Thesimulation unit 19 h reads from the facility performance information 26,the transformer capacity and the unit price of the transformer of 30 kVAand the transformer of 10 kVA. The simulation unit 19 h calculates adistribution loss caused by the replacement of the distributionfacility. The simulation unit 19 h, for example, calculates a voltageand a load current in the distribution facility after the replacementbased on: the information on voltage, load current and facilityperformance calculated for distribution facilities before thereplacement; and the information on the facility performance of thedistribution facility after the replacement. In one aspect, thesimulation unit 19 h calculates, when the transformer capacity of thetransformer is changed, a voltage and a load current in the transformerafter the replacement. The simulation unit 19 h calculates the amount ofpower loss in each distribution facility based on the load current ofeach distribution facility.

The simulation unit 19 h derives a change in the loss price based on achange in the amount of power loss in the replacement of thedistribution facility. The simulation unit 19 h, for example, derives achange in the loss price per unit time after the replacement based onthe amount of power loss before the replacement, thereby deriving achange in the loss price per year.

FIG. 26 is a diagram for explaining a change in the loss price caused bythe replacement of the distribution facility. As illustrated in FIG. 26,the transformer of 30 kVA has an amount of power loss per unit time of0.349 kWh and a loss price per unit time of 6 yen. In this case, theamount of power loss in a year is 127.543 kWh and the loss price is2,296 yen. By contrast, the transformer of 10 kVA has an amount of powerloss per unit time of 1.064 kWh and a loss price per unit time of 19yen. In this case, the amount of power loss in a year is 388.213 kWh andthe loss price is 6,988 yen.

The difference in the amount of power loss per unit time between thetransformer of 10 kVA and the transformer of 30 kVA is 0.715 kWh, andthe difference in the loss price per unit time therebetween is 13 yen.The difference in the amount of power loss between the transformer of 10kVA and the transformer of 30 kVA in a year is 261 kWh, and thedifference in the loss price therebetween in a year is 4,692 yen.

The simulation unit 19 h further calculates the difference in the unitprice in replacement of the transformer of 10 kVA with the transformerof 30 kVA. FIG. 27 is a diagram for explaining a change in the pricecaused by replacement of the distribution facility. Assuming that thenumber of transformers is three as illustrated in FIG. 14 and FIG. 15,the transformers of 30 kVA cost 480,000 yen (=160,000 yen×3) asillustrated in FIG. 27. By contrast, the transformers of 10 kVA cost360,000 yen (=120,000 yen×3). In this case, the difference in the pricebetween the transformer of 30 kVA and the transformer of 10 kVA is120,000 yen.

The simulation unit 19 h accumulates the loss price per year, therebyrunning a simulation of how many years it takes for the accumulated lossprice no reach the difference in the unit price caused by thereplacement of the distribution facility. FIG. 28 is an example diagramof comparison of the accumulated value of the loss price per year withthe difference in the unit price. The example in FIG. 28 indicates thataccumulation of a loss price per year of 4,692 for 26 years exceeds120,000 yen. While the comparison is made between the difference and theloss price per year, the comparison may be made with a loss price in adesired period, such as per month and per day.

The display control unit 19 g displays information on the result of thesimulation run by the simulation unit 19 h on the client terminal 30.FIG. 29 illustrates an example of display of the result of thesimulation. As illustrated in FIG. 29, for example, the display controlunit 19 g displays the accumulated value of the loss price per year andthe difference in the unit price on a graph. This makes it possible tograsp how much use of the distribution facility leads to a reduction inthe cost. The example in FIG. 29 indicates that the transformer of 30kVA has a smaller cost in the use for 26 years or longer, whereas thetransformer of 10 kVA has a smaller cost in the use for shorter than 26years, for example.

Advantageous Effects of the Second Embodiment

As described above, the loss calculating device 10 according to thepresent embodiment converts the amount of power loss into an amount ofmoney based on the unit price information 25. This makes it possible tograsp the amount of power loss as an amount of money.

[c] Third Embodiment

While the explanations have been made of the embodiments of thedisclosed device, the present invention may be embodied as variousdifference aspects besides the embodiments above. The followingdescribes other embodiments included in the present invention.

Distribution and Integration

The components of each device illustrated in the drawings are notnecessarily physically configured as illustrated. In other words, thespecific aspects of distribution and integration of each device are notlimited to those illustrated in the drawings. The whole or a part ofeach device may be distributed or integrated functionally or physicallyin desired units depending on various types of loads and usage, forexample. The retrieval unit 19 a, the associating unit 19 b, theacquiring unit 19 c, the first calculating unit 19 d, the secondcalculating unit 19 e, the totalizing unit 19 f, the display controlunit 19 g, and the simulation unit 19 h may be connected to the losscalculating device 10 as external devices via a network, for example.Alternatively, the retrieval unit 19 a, the associating unit 19 b, theacquiring unit 19 c, the first calculating unit 19 d, the secondcalculating unit 19 e, the totalizing unit 19 f, the display controlunit 19 g, and the simulation unit 19 h may be included in respectivedifferent devices. In this case, the respective devices are connectedvia a network to cooperate with one another, thereby carrying out thefunctions of the loss calculating device 10.

Loss Calculation Program

The various types of processing described in the embodiments can beperformed by a computer, such as a personal computer and a workstation,executing a computer program prepared in advance. The followingdescribes an example of a computer that executes a loss calculationprogram having functions similar to those of the embodiments withreference to FIG. 30.

FIG. 30 is an example block diagram for explaining the computer thatexecutes the loss calculation program according to the first to thethird embodiments. As illustrated in FIG. 30, a computer 100 includes anoperating unit 110 a, a speaker 110 b, a camera 110 c, a display 120,and a communication unit 130. The computer 100 further includes a CPU150, a ROM 160, a hard disk drive (HDD) 170, and a RAM 180. The units110 to 180 are connected to one another via a bus 140.

As illustrated in FIG. 30, the HDD 170 stores therein a loss calculationprogram 170 a in advance. The loss calculation program 170 a carries outfunctions similar to those of the retrieval unit 19 a, the associatingunit 19 b, the acquiring unit 19 c, the first calculating unit 19 d, thesecond calculating unit 19 e, the totalizing unit 19 f, the displaycontrol unit 19 g, and the simulation unit 19 h described in the firstand the second embodiments. The loss calculation program 170 a may beintegrated or distributed as needed. In other words, all the data storedin the HDD 170 are not necessarily stored in the HDD 170. Data requiredfor the processing alone may be stored in the HDD 170.

The CPU 150 reads the loss calculation program 170 a from the HDD 170and loads it on the RAM 180. This causes the loss calculation program170 a to function as a loss calculation process 180 a as illustrated inFIG. 30. The loss calculation process 180 a loads various types of dataread from the HDD 170 on an area allocated thereto on the RAM 180 asneeded. The loss calculation process 180 a performs various types ofprocessing based on the loaded various types of data. The losscalculation process 180 a includes the processing performed by theretrieval unit 19 a, the associating unit 19 b, the acquiring unit 19 c,the first calculating unit 19 d, the second calculating unit 19 e, thetotalizing unit 19 f, and the display control unit 19 g, and thesimulation unit 19 h illustrated in FIG. 1 and FIG. 22, specifically,the processing illustrated in FIG. 19 to FIG. 21, for example. All theprocessing units virtually provided on the CPU 150 do not necessarilyoperate on the CPU 150. A processing unit required for the processingalone may be virtually provided.

The loss calculation program 170 a is not necessarily stored in the HDD170 or the ROM 160 in advance. Each computer program may be stored in a“portable physical medium” inserted into the computer 100, such as aflexible disk (what is called an FD), a compact disc read only memory(CD-ROM), a digital versatile disc (DVD), a magneto-optical disc, and anintegrated circuit (IC) card. The computer 100 may acquire each computerprogram from the portable physical medium to execute the computerprogram. Alternatively, each computer program may be stored in anothercomputer or a server connected to the computer 100 via a public line,the Internet, a LAN, a wide area network (WAN), or the like. Thecomputer 100 may acquire each computer program from these devices toexecute the computer program.

The present invention can grasp a distribution loss of each distributionfacility.

All examples and conditional language recited herein are intended forpedagogical purposes of aiding the reader in understanding the inventionand the concepts contributed by the inventor to further the art, and arenot to be construed as limitations to such specifically recited examplesand conditions, nor does the organization of such examples in thespecification relate to a showing of the superiority and inferiority ofthe invention. Although the embodiments of the present invention havebeen described in detail, it should be understood that the variouschanges, substitutions, and alterations could be made hereto withoutdeparting from the spirit and scope of the invention.

What is claimed is:
 1. A non-transitory computer-readable recordingmedium having stored therein a program for causing a computer to executea process, the process comprising: calculating a load current of eachdistribution facility based on a sending voltage in power sourcefacilities and load information on a power consumption facility in anelectrical circuit including the power source facility, the distributionfacilities, and the power consumption facilities connected to oneanother to form the electrical circuit; calculating an amount of powerloss in each distribution facility based on the calculated load currentof each distribution facility; receiving a specification to changeperformance of any one of the distribution facilities in the electricalcircuit based on facility performance information including a unit priceof performance of the distribution facility; when specified distributionfacility is changed for specified performance, calculating amount ofpower loss of the specified distribution facility before and after thechange of the performance and converting the difference of calculatedamount of power loss of the specified distribution facility betweenbefore and after the change of the performance into an amount of moneyusing the unit price of performance of the distribution facility; anddisplaying amount of money converted by the converting in total anddifference of the unit price of the performance between before and afterthe change of the performance.
 2. The non-transitory computer-readablerecording medium according to claim 1, wherein the load information onthe power consumption facilities are acquired every predeterminedperiod; the calculating of the load current includes calculating theload current of each distribution facility in each predetermined periodis calculated based on the sending voltage in the power source facilityand the load information on the power consumption facilities acquiredevery predetermined period; and the calculating of the amount of powerloss includes calculating the amount of power loss in each predeterminedperiod in each distribution facility is calculated using the loadcurrent in each predetermined period calculated for each distributionfacility.
 3. The non-transitory computer-readable recording mediumaccording to claim 2, wherein the process further comprises: totalizingthe amount of power loss in each predetermined period calculated foreach distribution facility in units of the predetermined period and atype of the distribution facility; and displaying the amount of powerloss totalized in units of the predetermined period and the type of thedistribution facility.
 4. The non-transitory computer-readable recordingmedium according to claim 2, wherein the process further comprises:calculating the sum of the amount of power loss in each predeterminedperiod calculated for each distribution facility in units of a type ofthe distribution facility; and displaying the calculated sum of theamount of power loss in units of the type of the distribution facility.5. The non-transitory computer-readable recording medium according toclaim 1, wherein the process further comprises: converting the amount ofpower loss into an amount of money based on unit price informationindicating a unit price of electric power.
 6. A loss calculation methodexecuted by a computer, the method comprising: calculating a loadcurrent of each distribution facility based on a sending voltage inpower source facilities and load information on a power consumptionfacility in an electrical circuit including the power source facility,the distribution facilities, and the power consumption facilitiesconnected to one another to form the electrical circuit; calculating anamount of power loss in each distribution facility based on thecalculated load current of each distribution facility; receiving aspecification to change performance of any one of the distributionfacilities in the electrical circuit based on facility performanceinformation storing a unit price of performance of the distributionfacility; when specified distribution facility is changed for specifiedperformance, calculating amount of power loss of the specifieddistribution facility before and after the change of the performance andconverting the difference of calculated amount of power loss of thespecified distribution facility between before and after the change ofthe performance into an amount of money using the unit price ofperformance of the distribution facility; and displaying amount of moneyconverted by the converting in total and difference of the unit price ofthe performance between before and after the change of the performance.7. A loss calculating device comprising: a first calculating unit thatcalculates a load current of each distribution facility based on asending voltage in power source facilities and load information on apower consumption facility in an electrical circuit including the powersource facility, the distribution facilities, and the power consumptionfacilities connected to one another to form the electrical circuit, asecond calculating unit that calculates an amount of power loss in eachdistribution facility based on the calculated load current of eachdistribution facility; a receiving unit that receives a specification tochange performance of any one of the distribution facilities in theelectrical circuit based on facility performance information storing aunit price of performance of the distribution facility; a totalizingunit that when specified distribution facility is changed for specifiedperformance, calculates amount of power loss of the specifieddistribution facility before and after the change of the performance andconverts the difference of calculated amount of power loss of thespecified distribution facility between before and after the change ofthe performance into an amount of money using the unit price ofperformance of the distribution facility; and a display control unitthat controls to display amount of money converted by the totalizingunit in total and difference of the unit price of the performancebetween before and after the change of the performance.